Ur (continent)

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Ur was a supercontinent that formed 3,000 million years ago (3 billion) in the early Archean eon;[1] perhaps the oldest continent on Earth, half a billion years older than Arctica, but it may have been preceded by one other supercontinent, Vaalbara, which is suggested to have formed about 3,600 to 3,100 million years ago.[2]

Ur joined with the continents Nena and Atlantica about 1,000 million years ago (1 billion) to form the supercontinent Rodinia. Ur survived as a single unit until it was sundered when the supercontinent Pangaea broke apart into Laurasia and Gondwana.[3]

Formation and breakup[edit]

Rocks that made up Ur are now parts of Africa, Australia, and India.[3]

In the early period of Ur's existence, it was probably the only continent on Earth, and as such is considered a supercontinent, though it was probably smaller than present-day Australia.

When Ur was the only continent on Earth, all other land was in the form of small granite islands and small land-masses like Kenorland[dubious ] that were not large enough to be continents.

Timeline[edit]

All dates below are approximate.

  • 3 billion years ago, Ur formed as the only continent on Earth.
  • 2.8 billion years ago, Ur was a part of the major supercontinent Kenorland.
  • 2 billion years ago, Ur was a part of the major supercontinent Columbia.
  • 1 billion years ago, Ur was a part of the major supercontinent Rodinia.
  • 550 million years ago, Ur was a part of the major supercontinent Pannotia.
  • 300 million years ago, Ur was a part of the major supercontinent Pangaea.
  • 208 million years ago, Ur was torn apart into parts of Laurasia and Gondwana.
  • 65 million years ago, the African part of Ur was torn apart as part of India.
  • Present, Ur is part of Australia and Madagascar.

Notes[edit]

References[edit]

  1. ^ Zubritsky, Elizabeth. "In the beginning, there was Ur". Endeavors. University of North Carolina at Chapel Hill. Retrieved 28 June 2015. 
  2. ^ Lerner & Lerner 2003
  3. ^ a b Zubritsky 1997

External links[edit]